Limonene is a 10-carbon monoterpene with the formula C10H16 that is an isomer of Tetrahydrodiclopentadiene, also known as JP-10 jet fuel, a high energy density and expensive fuel. When dimerized, limonene can be converted into a high energy density (HED) jet fuel with similar properties to JP-10 jet fuel.
Limonene is obtained as a byproduct of citrus processing from rind of citrus fruits. The major barrier for widespread application of limonene in a variety of products has largely been the relatively high price, high pricing volatility, and supply side uncertainty associated with citrus limonene, which is the largest source of the compound. Intrinsically limonene is a very versatile and useful intermediate chemical and fuel. However, in practice its utilization has been limited due to its high per unit price and limited availability. Due to limited volumetric availability of terpenes such as limonene, which are mostly plant-derived and produced in small quantities, the approach of using limonene and other terpenes for producing significant volumes of jet fuel has not been feasible and hence has not been pursued by the industry to date.
The need remains for a way to produce high volumes of terpenes, such as limonene, from feedstocks that are readily available, abundant, and cheap.
There also is a need to break the bottleneck associated with biologically producing economically competitive replacements for petroleum derived fuels and chemicals on a very large scale. There is a need for bioprocesses with compact, vertical scaling as opposed to traditional biofuel operations that scale horizontally and are land intensive. In this way, the food versus fuel question and conflicts over land use and disruption of natural habitats can be more readily avoided. There is a need for monoterpene sources with predictably higher margins and greater supply security.